RE: {minutes} HTML WG media telecon 2013-06-11 - MSE status and bug discussion

Minutes -> http://www.w3.org/2013/06/11-html-media-minutes.html


   [1]W3C

      [1] http://www.w3.org/


                               - DRAFT -

                  HTML Media Task Force Teleconference

11 Jun 2013

   [2]Agenda

      [2] http://lists.w3.org/Archives/Public/public-html-media/2013Jun/0012.html


   See also: [3]IRC log

      [3] http://www.w3.org/2013/06/11-html-media-irc


Attendees

   Present
          davide, Michael_Thornburgh, joesteele, pladd, Cyril,
          johnsim, Aaron_Colwell, markw, adrianba, BobLund,
          ddorwin, paulc

   Regrets
   Chair
          Aaron Colwell

   Scribe
          Adrian Bateman

Contents

     * [4]Topics
         1. [5]Roll call, introductions and selection of scribe
         2. [6]Review of action items and issues
         3. [7]MSE status and bugs
         4. [8]Adjournment
     * [9]Summary of Action Items
     __________________________________________________________

   <trackbot> Date: 11 June 2013

   <scribe> scribenick: adrianba

   <scribe> scribe: Adrian Bateman

   <acolwell>
   [10]http://lists.w3.org/Archives/Public/public-html-media/2013J

   un/0012.html

     [10] http://lists.w3.org/Archives/Public/public-html-media/2013Jun/0012.html


Roll call, introductions and selection of scribe

   acolwell: done

Review of action items and issues

   acolwell: none

MSE status and bugs

   acolwell: since the last call i published 2 spec updates
   ... on jun 1 and jun 5
   ... tried to tackle as many of the pre-LC bugs as i could
   address
   ... please take a look
   ... still 11 bugs outstanding to discuss

   <paulc> Sorry I was late. Computer problems.

   acolwell: questions?

   <scribe> Chair: Paul Cotton

   <paulc> Link to open bugs:
   [11]https://www.w3.org/Bugs/Public/buglist.cgi?query_format=adv

   anced&product=HTML%20WG&component=Media%20Source%20Extensions&b
   ug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&list_id=1
   5288

     [11] https://www.w3.org/Bugs/Public/buglist.cgi?query_format=advanced&product=HTML%20WG&component=Media%20Source%20Extensions&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&list_id=15288


   -> [12]http://tinyurl.com/6pdnzej


     [12] http://tinyurl.com/6pdnzej


   Open bugs

   <paulc>
   [13]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22148


     [13] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22148


   Bug 22148
   [14]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22148


     [14] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22148


   Request that we reconsider adding jitter to video quality
   metrics

   <paulc>
   [15]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22148#c3


     [15] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22148#c3


   paulc: Most recent comment is from Jerry
   ... this has a specific proposal right in it

   acolwell: this got posted yesterday so i haven't had a bunch of
   time to think about it
   ... what is the application going to do with this information
   ... if you're starting to see large delays then you should see
   the dropped count increase

   <paulc> Jerry is out this week, so Adrian is responding.

   <paulc> This gives another indication of the quality of the
   presentation and the app will want to fall back to a lower
   quality media file.

   acolwell: the other question is could this expose user agent
   specific behaviour?
   ... if different UAs use different delays for when they
   consider to drop a frame, could that be problematic
   ... is this something people are worried about?

   markw: from what we understand, UAs could take different
   approaches before dropping so this metric allows you to detect
   that there are problems with playback before you get to dropped
   frames

   paulc: mark, do you support adding this feature request?

   markw: yes, because you need this in addition to dropped frames
   to allow consistent behaviour

   paulc: shall we move on to another and allow more time to think
   about this?

   Cyril: why is this on the video quality element and not on the
   media source object?

   acolwell: the reason this was added to the video quality object
   is because they are not MSE specific
   ... considered as an initial proposal to HTML5 and applies
   whether MSE is used or not

   <paulc> Bu 22138:
   [16]https://www.w3.org/Buggs/Public/show_bug.cgi?id=22138


     [16] https://www.w3.org/Buggs/Public/show_bug.cgi?id=22138


   acolwell: waiting for the person to respond

   adrianba: recommend resolving NEEDSINFO until we get the
   information needed to make the bug actionable

   paulc: i will add that note to the bug

   Bug 22137:
   [17]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22137


     [17] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22137


   acolwell: this is about changing the number of tracks during
   playback
   ... this has come back a number of times
   ... i tried to add a proposal to not have it become too
   complicated

   <paulc> June 11 reply:
   [18]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22137#c4


     [18] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22137#c4


   acolwell: suggestion is to allow it to be accepted but not
   guaranteed to be played
   ... looks like the filer is okay with this
   ... but want the group to decide if this is something we want
   to do this version or not
   ... haven't discussed as a group

   <paulc> We request the W3C relax the restrictions in section 11
   that “apply to all initialization segments in a byte stream” –
   particularly requirements #1 (“The number and type of tracks
   must be consistent”) and #3 (“Track IDs must be the same across
   initialization segments if the segment describes multiple
   tracks of a single type”) – at least for audio tracks.

   paulc: this is the key questions

   <paulc> Current spec is in section 12.

   Cyril: you talk about a default flag in the track - what does
   this mean?

   acolwell: in mpeg4 there is a default track flag, i think, not
   sure which box it is - tracks can be marked as the default for
   playback
   ... most formats supporting multiple tracks have a way to
   indicated which should be played by default

   Cyril: you may have multiple tracks enabled

   acolwell: if you don't have a default then you pick the first
   in the init segment

   BobLund: not sure i understand the solution
   ... UA does not need to support multiple audio and video
   tracks?

   acolwell: no, in a single sourcebuffer, if there is one audio
   and one video track
   ... then you add another segment with 2 audio and 2 video
   tracks
   ... then the UA isn't required to expose the new tracks
   ... different to the current track, which would reject playback
   all together
   ... suggesting that don't reject it but don't guarantee
   playback

   BobLund: so if the first init segment exposes multiple tracks
   then all have to be available?

   acolwell: yes
   ... we'd need to decide what happens if the number reduces
   ... the text of the spec was written assuming the number
   doesn't change

   Cyril: you want to bound the number of tracks by the number in
   the first init segment?

   acolwell: my concern is that if things change during playback
   it is hard to ensure resources are available during playback
   ... so during the first init this is the time the media engine
   can reserve the appropriate resources
   ... and it is optional to add new resources later
   ... even if there are multiple tracks in the first init segment
   then the UA isn't necessarily required to support them all

   BobLund: i think the HTML spec in the media section defines
   what UAs should do with multiple tracks
   ... and i am happy with your proposed solution

   <paulc> Q from correspondent: Does an HTML5 UA have a concept
   of user preferences for audio language or accessibility?

   <paulc> Re above question: bob said he did not know if such
   guidance existed.

   <paulc> Adrian: Microsoft needs to check on acolwell's
   proposal.

   <paulc> Adrian: Just need more time to review.

   Bug 22136:
   [19]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22136


     [19] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22136


   <paulc> See
   [20]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22136#c8


     [20] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22136#c8


   acolwell: i think they accept the proposal so i just need to
   make the change

   <paulc>
   [21]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22135


     [21] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22135


   <paulc> Ade's response:
   [22]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22135#c4


     [22] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22135#c4


   acolwell: this is a request for track switching that is more
   general than mse
   ... i don't think we should change the spec at this point

   <paulc> Re solution to 22136 is the support mandatory?

   adrianba: on 22136, is this support mandatory?

   acolwell: i was trying to specify a mandatory base line so that
   you don't get a decode error depending on if support is there
   ... i think from chrome's pov i think what i described worked

   <paulc> To be clear we are talking about 22136 here.

   <paulc> We will hold off implementing the fix for 22136 and
   Adrian will respond on the bug with his position.

   <paulc> Back 22135:

   paulc: back on 22135

   <paulc> Ade's response:
   [23]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22135#c4


     [23] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22135#c4


   paulc: does anybody else want to speak to this?
   ... done

   Bug 22134:
   [24]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22134


     [24] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22134


   acolwell: need to think about this some more
   ... spec isn't clear on when content is rejected

   paulc: that one is in your court then

   <paulc>
   [25]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22117


     [25] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22117


   paulc: bug says please provide text and suggested location

   acolwell: still not quite sure what cyril is looking for

   Cyril: i looked at all the must statements and most are related
   to UA
   ... but some others are related to media segments
   ... media segments must have this or that
   ... which seemed like normative statements for generation of
   content

   acolwell: i don't understand the difference between what a UA
   must do to play it vs. to create it
   ... the spec outlines what happens in the UA

   paulc: we could reword so it says the UA must do something with
   the media segment

   Cyril: worried about people suggesting creating segments that
   are not conforming

   acolwell: they would be segments that MSE UAs can't play

   Cyril: was looking at this for writing conformance tests

   adrianba: happy to edit the changes into the spec if someone
   writes them up

   Cyril: i can do that

   paulc: Cyril will identify the new text - change A to B

   Cyril: shall i add them to the bug?

   paulc: yes

   22112: [26]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22112


     [26] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22112


   paulc: editorial, assigned to adrianba

   22110: [27]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22110


     [27] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22110

   acolwell: also editorial

   adrianba: wasn't sure what text to put there

   acolwell: if the JS layer wants to indicate a decode error this
   is how
   ... don't want to enumerate all the reasons

   paulc: cyril, can you give us an example

   Cyril: think the text that an app can signal a decode error but
   not sure when this would be used at all

   acolwell: if the app does any parsing and doesn't get what it
   expects it would use this

   Cyril: why wouldn't it get another segment

   acolwell: MSE replaces the network layer and that layer is able
   to provide decode and network errors
   ... and this provides that mechanism in MSE

   adrianba: assign to me and i'll update the text

   <paulc>
   [28]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22109


     [28] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22109


   22109 -
   [29]https://www.w3.org/Bugs/Public/show_bug.cgi?id=22109


     [29] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22109


   acolwell: this is editorial, just need to figure out what to
   say

   adrianba: would like to suggest that when someone files an
   editorial bug suggesting to rename something when please use
   propose a new name

   acolwell: i will think about this

   Bug 21431
   [30]https://www.w3.org/Bugs/Public/show_bug.cgi?id=21431


     [30] https://www.w3.org/Bugs/Public/show_bug.cgi?id=21431

   paulc: did the changes but not marked as resolved

   <paulc> See
   [31]https://www.w3.org/Bugs/Public/show_bug.cgi?id=21431#c14


     [31] https://www.w3.org/Bugs/Public/show_bug.cgi?id=21431#c14


   acolwell: glenn's comment was here are things that need to be
   done but there will be more
   ... so i left it open for glenn to add any more

   paulc: recommend sending a personal note to glenn
   ... not clear if we will have resolved all bugs in 2 weeks
   ... when we do that we will do a CfC inside the TF to go to LC
   ... you will have seen my regrets for next tuesday - i come
   back the following monday so either you get a late agenda,
   someone else does it, or i do it today as a proforma

   adrianba: i'm fine with the day before

   acolwell: i'm fine with that too

Adjournment

   paulc: adjourned

Summary of Action Items

   [End of minutes]


_____________________
From: Paul Cotton [mailto:Paul.Cotton@microsoft.com] 
Sent: Thursday, June 6, 2013 10:21 AM
To: public-html-media@w3.org
Subject: {agenda} HTML WG media telecon 2013-06-11 - MSE status and bug discussion

The HTML WG media teleconference meeting will occur on 2013-06-11 for up to 60 minutes from 15:00Z to 16:00Z.
 
http://timeanddate.com/s/2dh4

 
Tokyo midnight, Amsterdam/Oslo 17:00, London/Dublin 16:00, New Jersey/York 11:00, Kansas City 10:00, Seattle/San Francisco 08:00.
 
Chair of the meeting: Paul Cotton
Scribe: TBD
 
(See the end of this email for dial-in and IRC info.)
 
== Agenda ==
 
1. Roll call, introductions and selection of scribe
 
2. Previous meeting minutes
http://www.w3.org/2013/05/28-html-media-minutes.html 
 
3. Review of action items and issues
https://www.w3.org/html/wg/media/track/

No MSE-related actions.
 
4. MSE status and bugs
 
a) Media Source Extensions editor's draft: 
http://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html 
Status as of Jun 6:  Last updated on May 5.
 
b) Media Source Extensions bugs: 
http://tinyurl.com/6pdnzej 
Status as of Jun 6: 9 bugs.  See list at end of this agenda.
 
c) Editors actions on pre-Last Call bugs
 
5. Any other business
 
6. Chair and Scribe for next meeting
 
7. Adjournment
 
== Dial-in and IRC Details ==
 
Zakim teleconference bridge:
   +1.617.761.6200, conference 63342 ("media")
https://www.w3.org/Guide/1998/08/teleconference-calendar#s_5366

 
Supplementary IRC chat (logged):
   #html-media on irc.w3.org port 6665 or port 80
 
Paul Cotton, Microsoft Canada
17 Eleanor Drive, Ottawa, Ontario K2E 6A3
Tel: (425) 705-9596 Fax: (425) 936-7329
 
ID▼ 
Summary 
Changed 
22138 
Frame removal 
2013-05-28 
22137 
changes in number of audio tracks during advert insertion 
2013-05-29 
22136 
Inband Storage for SPS/PPS in ISO BMFF 
Wed 15:41 
22135 
Changing Source Buffers 
2013-05-24 
22117 
Add a conformance section 
Wed 16:08 
22112 
Merge appendBuffer and appendStream text 
2013-05-23 
22110 
Javascript decoding data 
2013-05-23 
22109 
Use of the word sequence 
2013-05-23 
21431 
Specify splicing behavior for text tracks 
Sat 21:38 
9 bugs found.

Received on Tuesday, 11 June 2013 16:08:34 UTC